Fumie Costen

Development of a CUDA Implementation of the 3D FDTD Method

The use of general-purpose computing on a GPU is an effective way to accelerate the FDTD method. This paper introduces flexibility to the theoretically best available approach. It examines the performance on both Tesla- and Fermi-architecture GPUs, and identifies the best way to determine the GPU parameters for the proposed method.

Three-dimensional laser microvision

A three-dimensional (3-D) optical imaging system offering high resolution in all three dimensions, requiring minimum manipulation and capable of real-time operation, is presented. The system derives its capabilities from use of the superstructure grating laser source in the implementation of a laser step frequency radar for depth information acquisition. A synthetic aperture radar technique was also used to further enhance its lateral resolution as well as extend the depth of focus. High-speed operation was made possible by a dual computer system consisting of a host and a remote microcomputer supported by a dual-channel Small Computer System Interface parallel data transfer system. The system is capable of operating near real time. The 3-D display of a tunneling diode, a microwave integrated circuit, and a see-through image taken by the system operating near real time are included. The depth resolution is 40 mum; lateral resolution with a synthetic aperture approach is a fraction of a micrometer and that without it is approximately 10 mum.

On the Solution of 3-D Frequency Dependent Crank-Nicolson FDTD Scheme

Unconditional stability of the Crank-Nicolson Finite Difference Time Domain (CN-FDTD) method permits us to use time steps over the Courant-Friedrich-Lewy (CFL) limit of conventional FDTD method. However, in this work it was realized that, when the time step is set above CFL limit the coefficient matrix arising from Crank-Nicolson method is no longer diagonally dominant and iterative solvers require longer solution time in each FDTD iteration. Frequency dependent CN-FDTD (FD-CN-FDTD) scheme for Debye media is formulated and numerical tests are performed with two widely used sparse iterative solvers, Bi-Conjugate Gradient Stabilised (BiCGStab) and Generalised Minimal Residual (GMRES), for comparison. BiCGStab outperforms GMRES in every aspect of the study.

Efficient Parallel LOD-FDTD Method for Debye-Dispersive Media

The locally one-dimensional finite-difference time-domain (LOD-FDTD) method is a promising implicit technique for solving Maxwells equations in numerical electromagnetics. This paper describes an efficient message passing interface (MPI)-parallel implementation of the LOD-FDTD method for Debye-dispersive media. Its computational efficiency is demonstrated to be superior to that of the parallel ADI-FDTD method. We demonstrate the effectiveness of the proposed parallel algorithm in the simulation of a bio-electromagnetic problem: the deep brain stimulation (DBS) in the human body.

Huygens Subgridding for 3-D Frequency-Dependent Finite-Difference Time-Domain Method

Subgridding methods are often used to increase the efficiency of the wave propagation simulation with the Finite-Difference Time-Domain method. However, the majority of contemporary subgridding techniques have two important drawbacks: the difficulty in accommodating dispersive media and the inability for physical interfaces to cross the subgridding interface. This paper presents an extension of the frequency-dependent Huygens subgridding method from one dimension to three dimensions. Frequency dependency is implemented via the Auxiliary Differential Equation approach using the one-pole Debye relaxation model. Numerical experiments indicate that subgridding interfaces can be placed in various Debye media as well as across the physical interface .

An application of smart antenna systems for archiving networks in TV studios

Data archiving networks and electronic media libraries for video and audio broadcasting have gained a large interest recently. This paper proposes the use of smart (adaptive) antennas for HIPERLAN/2 (HIgh PERformance Radio Local Area Network/2) in order to increase the data rate and user capacity targeting wired LAN replacement in modem TV broadcasting studio environments. Spatial channel models are necessary for the proper design, analysis and implementation of smart antenna systems. A simple 2D ray tracing indoor channel model for predicting propagation characteristics inside a room of arbitrary dimensions and wall properties is presented. The simulation model gives fast estimates of the power-delay profile (PDP) and direction of arrival (DOA) information based on the geometrical optics (GO) theory taking into account double reflections. The effects of the relative positions of the transmitter and the receiver, room dimensions as well as the number of transmitters are investigated.

Extension of the FDTD Huygens subgridding to frequency dependent media

A wide range of wireless system developments require knowledge of the distribution of electromagnetic fields from various sources in humans. As experimental assessment is ethically unacceptable, high-resolution numerical dosimetry is needed. The finite-difference time-domain method is the most appropriate due to its simplicity and versatility. Reduction in demands on computational resources can be achieved using subgridding techniques. This paper rigorously introduces frequency dependency to one of the most promising subgridding techniques, Huygens subgridding. The validity of the Huygens surface in lossy media, as well as on the physical interface, is intensively studied.

Investigation to make best use of LSF with high efficiency

A network of commodity workstations offers an effective platform for large scale parallel processing. The effectiveness of such systems can be greatly improved by efficient cluster management software. In this paper, we focus upon the widely used load sharing facility (LSF), and investigate its ability to run both parallel and serial simulations and increase the throughput of jobs. The experiment shows that LSF does a good job in terms of balancing the load for serial jobs and avoiding the machines with high processor utilization rates. Using the result of the experiment, we created a useful diagnostic tool for assessing the impact of load balancing software.

Performance of Streaming SIMD Extensions Instructions for the FDTD Computation

The utilization of vector-arithmetic logic units is a promising way to speed up FDTD computations from the viewpoint of hardware acceleration. This paper studies how a streaming SIMD extensions (SSE) implementation can be effi ciently developed, and the situation where SSE is benefi cial for FDTD computations.

Modelling em wave interactions with human body in frequency dependent Crank Nicolson method

A simulation model of the human body is developed in frequency dependent Crank Nicolson finite difference time domain (FD-CN-FDTD) method. Numerical simulation of electromagnetic wave propagation inside the human head is presented. Advantages of using time discretization beyond the Courant Friedrich-Lewy (CFL) limit in FD-CN-FDTD method are shown. Parallelization using Open Multi-Processing (OpenMP) in a shared memory architecture is performed and the achieved computational efficiencies are shown.